This invention relates to microcircuits and more particularly to a ceramic substrate provided with metal filled via holes for use in constructing hybrid microcircuits for microwave systems.
Microwave components that operate at frequencies on the order of gigahertz are preferably made of (gallium arsenide) GaAs semiconductor material because of the high mobility of electrons in the material. Moreover, because such microwave components are operating with band waves that are on the order of millimeters and centimeters in length, and the conducting paths of microcircuits are generally of the same order in length, the mechanical construction and the electrical performance of microwave circuits are closely interrelated. Thus, in hybrid microwave circuits, the conductive paths provided for connecting the components of the circuit to ground are not just paths of minimal significance but must be viewed as circuit elements themselves in that they provide distributed inductance depending on their length which must be taken into consideration. Moreover, because of the gigahertz frequency at which components of microwave circuits operate they generate a large amount of internal heat which must be carried away to enable the circuits to perform properly.